This invention relates to catalyst, a method for producing catalyst, and a process for using the catalyst in the polymerization of olefins. The invention is particularly directed to the preparation of olefin polymerization catalysts which contain a prepolymer.
A number of the later generation high activity polymerization catalysts are prepared by processes which result in solid particulate catalysts having varying degrees of catalyst fines. The use of fine particulate polymerization catalyst in many cases leads to the production of polymer having undersirable levels of fine particulate polymer. One of the techniques that has been used in the past to reduce the production of polymer fines has been to treat the particulate polymerization catalyst with a prepolymer. Two examples of such processes are disclosed in U.S. Pat. Nos. 4,325,837 and 4,326,998, the disclosures of which are incorporated herein by reference.
While the addition of prepolymer has often been found to be effective in the reduction of polymer fines, there is still a need for greater improvement.
An object of the present invention is to provide a method for carrying out prepolymerization of a catalyst in such a fashion as to provide further improvements in the reduction of polymer fines.
Another object of the present invention is to provide a novel catalyst resulting from this new prepolymerization technique.
Still another object of the present invention is to provide a process for preparing polymers using the new prepolymerized catalyst.
Other aspects, objects, and advantages of the present invention will become apparent to those skilled in the art having the benefit of this disclosure.